1. Field of the Invention
The present invention relates in general to an equipment enclosure. More specifically, the present invention relates to heat transfer from an equipment enclosure housing a plurality of circuit boards.
2. Description of the Related Art
To provide consumers with increased bandwidth for transmitting and receiving telecommunications information, fiber in the loop (FITL) networks have been developed. With these networks, optical fiber carries digital information to a location close (perhaps within 1000') to the consumer. In this manner, the information does not travel far over conventional copper wiring, and signal degradation is less of a problem. The optical fiber may carry both conventional telephone traffic and broadband services, such as video on demand, teleconferencing, high speed internet access, etc. In fiber in the loop networks, optical network units receive digital optical signals from fiber optic cable, perform optical-to-electric (and electric-to-optical) conversion and distribute digital electric signals to the consumers.
The optical network units are to house printed circuit boards, and the components thereon generate heat. The circuitry is very sensitive to moisture and other environmental conditions. Thus, the circuit boards must be housed in an enclosure which dissipates heat and is water tight. Furthermore, because the radius of distribution of the optical network unit is relatively small, fiber in the loop networks require many optical network units. For this reason and because the optical network units must be very reliable, active heat transfer components, which require maintenance, cannot be used.
In use, the optical network units may be positioned on the ground or on utility poles. Therefore, small size and light weight are also desirable.